Cross-domain authentication ASP.net MVC

Question

I have two different web application built with ASP.net MVC. This two application may not be running in the same server nor in the same domain.

I would like that if a us

Answer 1

Thanks to the answer of @Kaushik Thanki I have implemented some code that fix my problem. I will post here the solution that it works for me, even if it is not the optimus.

First of all, I have implemented in A a method to make a Post request to B. Inside this method I take the id of the user and I make a hash of it with some other parameter and passwords. Then, I send to B the user id, the hash, and a boolean to choose between login and logout.

private void SendPostRequest(bool login)
        {
            // Create the combine string
            string data = // userId combined with more stuff

            // Create the hash of the combine string
            HashAlgorithm algorithm = MD5.Create();
            byte[] hash = algorithm.ComputeHash(Encoding.UTF8.GetBytes(data));
            StringBuilder sb = new StringBuilder();
            foreach (byte b in hash)
                sb.Append(b.ToString("X2"));

            string encriptedData = sb.ToString();

            // Fill the url with the path and the data
            string url = "http://localhost/xxx/yyy/ExternalAuthentication/Login?id=" + _cachedCustomer.Id + "&hash=" + encriptedData + "&login=" + login.ToString();

            // Make the Post request
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream resStream = response.GetResponseStream();
        }

After it, I have created in B a new class to handle the login logic. I have use a HttpContext.Current.Application variable to store the status of the authentication:

public class ExternalAuthenticationController : Controller
        {

            public ActionResult Index()
            {
                return View();
            }

            public ActionResult Login(string id, string hash, string login)
            {
               // Create the combine string
               string data = //user id + same stuff than in A;

               // Create the hash of the combine string
               HashAlgorithm algorithm = MD5.Create();
               byte[] hashArray =    algorithm.ComputeHash(Encoding.UTF8.GetBytes(data));
               StringBuilder sb = new StringBuilder();
               foreach (byte b in hashArray)
                  sb.Append(b.ToString("X2"));
               string originalHash = sb.ToString();

               // Compare the two hash. If they are the same, create the variable
               if (hash.CompareTo(originalHash) == 0)
               {

               if (System.Web.HttpContext.Current.Application["Auth"] == null)
               {
                   System.Web.HttpContext.Current.Application["Auth"] = false;
               }

               if (Convert.ToBoolean(login))
               {
                   System.Web.HttpContext.Current.Application["Auth"] = true;
               }

              else
              {
                  System.Web.HttpContext.Current.Application["Auth"] = false;
              }
             }
         }

Probably, the answer provided by @vijay shiyani is better and more generalistic, but from my point of view it requires a lot of time to implement it.